Stoker furnace



June 2,- 1942. c. L. MYERS I 2,284,760

STOKER FURNACE Original Filed June 3, 1936 Patented June 2, 1942 i Iican Engineering Company, Philadelphia, Pa., a corporation ofPennsylvania Original application June 3, 1936, Serial No.,

1939, Serial No. 274,719

2 Claims. (01. 122-4) This application is a division of my co-pendingapplication filed June 3, 1936, under Ser. No. 83,281, and now issued asPatent 2,185,865, Jan.

2, 1940, and the invention embodied herein relate's to stoker furnaces,and more particularly to stokers of the inclined grate, multiple retortunderfeed type.

One object of the present invention is to provide a novel and highlyimproved stoker of the stated character, capable of functioningthroughout the operating range of the furnace to effect completecombustion of the fuel with the use of a minimum of excess air, therebyinsuring maximum furnace temperatures under all conditions of operation.1

Another object is to provide an improved stoker construction whichrequires a minimum of headroom, and therefore is adapted for use incommercial plants of varied sizes.

Another object is to provide in a stoker of the stated character a novelash disposal means for the refuse fed from the stoker.

. A more specific object is to provide in a stoker of the statedcharacter a slag pit for receiving the residue fed from the stokerwherein such residue is maintained in a liquid state, and anycombustible matter contained in such residue separates therefrom andfloats on top of the molten mass where it is brought into direct contactwith a combustion supporting gas and com pletely burned before themolten residue is drawn from the furnace. I

A further object is' to provide in a stoker furnace, novel means forliquefying and maintaining in a liquid state the residue fed from thestoker to the slag pit, and to provide means for directing air over thetop of theslag pit and into direct contact with the combustible matterseparating from the refuse as the latter is liquefied to effect completeburning thereof, said aid thereafter passing over the fuel bed of thestoker where it combined with the combustible gases driven from the fuelto insure complete combustion thereof.

Other and further objects will become apparent as the description of theinvention progresses.

Of the drawing the single figure is a sectional elevational view takenthrough one of the retorts of the stoker showing a still furthermodification of the present invention.

The drawing discloses a furnace fired by an underfeed stoker 3comprising alternately disposed retorts 4 and tuyere rows 5. The lowerend of the stoker terminates in an extended overfeed section I0'I whichis constantly vibrated Divided and this application May 20,

by any suitable vibrating mechanism indicated at I02 to feed the fuelfed from the stoker 3 proper into a slag pit 14 disposed at the rear endthereof. Fuel is fed to the retorts from hoppers 6 by a series of fuelfeeding rams operating in cylinders 1 and driven by any suitable powermechanism 8. Fuel is underfed along the retorts by a series of, pushers9 mounted in the bottoms of the retorts and operatively connected to thepower mechanism 8 by a link and lever mechanism I0.

The overfeed section IOI is cooled by a series of fluid conducting tubesI03 mounted in cooling relation therewith. Tubes'l03 are connected atthe lower ends thereof to a header I04 disposed beneath the stoker, andsecured to a suitable framework I05 and terminate at their upper ends ina header I06, also secured to said framework I05. The framework I05 isoperatively connected to the vibrating mechanism I02, and consequent lythe impulses imparted thereto by said mechanism are transmitted to theoverfeed section IOI through tubes I03. This vibratory movement ofoverfeed section IOI effectively feeds the fuel and refuse therealong toslag pit W.

The front wall I01, and the bottom wall I09 of slag pit I I in thepresent instance may comprise a series of air cooled refractory blocksI08 and H0 respectively. The rear wall of the furnace consists of aseries of block covered tubes I I I extending upwardly from atransversely disposed header II2. Tubes III are bent so asto extendforwardly and upwardly, as shown at II3, to form an arch II l overlyingthe slag pit I I and the overfeed section IIlI of the stoker, said tubesterminating at their upper ends in the mud drum H5 of the boiler. Theside walls II6 of the furnace may be constructed of a series of aircooled refractory blocks III, or of any other heat resistive means.

In this construction a series of nozzles 5| extend through the rear wallof the furnace and direct air at high velocities over the top of theslag pit to effect burning of any combustible material contained in therefuse. This air is then directed over the top of the fuel bed to effectcomplete burning of the combustible gases driven from the fuel. In thisconstruction also by virtue of arch II4 an extremely hot zone is createdover the slag pit and the overfeed section of the stoker whereby therefuse fed thereto is maintained in a liquid state. This liquid ash maybe withdrawn from the pit from time to time through a suitable tap 14.In this construction it will be noted that the fuel feeding elements 9of the stoker 3 are located a considerable distance from the rear mostend of the overfeed section thereof, and thus are shielded from themolten slag forming in the furnace by green fuel. Burners 66 may also beprovided in the side walls of the furnace to supply additional heatthereto when desired. Nozzles 5l may also have connected thereto branchpipes 61 for conducting an auxiliary fuel to the furnace from a supplyline 65 if it is so desired.

From the foregoing description it is seen that by reducing the ashcontent of the fuel to a liquid state, troublesome ash handling problemsare completely eliminated. It is also seen that by treating the ash inthis manner the fixed carbon and other combustible matter containedtherein separates from the ash and floats on top of the molten mass.This combustible matter being directly exposed to incoming air iscompletely burned and as a result of the combustible matter contained inthe fuel fed to the stoker is consumed, with the use of a minimum ofexcess air. The furnace therefore operates at high efliciencies inasmuchas the gases generated therein are maintained at maximum temperatures.It is also seen that by passing a certain quantity of air over the fuelbed, as well as over the combustible matter floating at the top of theash pit it is unnecessary to feed all of the air for combustion purposesthrough the grates of the stoker. Blowing of the fuel from the fuel bedis thus prevented, and as a result the fuel bed remains normally uniformthroughout the operation of the furnace. By treating the ash in thenovel manner set forth herein, it is also apparent that a relativelyshallow slag pit may be provided, and consequently the headroomrequirements of the unit as a whole are reduced to a minimum.

While the embodiment herein shown and described is admirably adapted tofulfill the objects primarily stated, it is to be understood that theinvention is not to be limited thereto since it may be embodied in otherform, all coming within the scope of the claims which follow.

What is claimed is:

1. An overfeed section for stoker furnaces comprising, a fuel supportingportion, fluid conducting tubes mounted in cooling relation with saidfuel supporting portion and forming a support therefor, headersconnected to the opposite ends of said tubes, a framework for supportingsaid headers, and means comprising a vibratory mechanism operativelyconnected to said framework for imparting rapid vibratory impulsesthereto and consequently to said tubes and fuel supporting portionwhereby the fuel supported on said fuel supporting portion isprogressively advanced from one end thereof to the other.

2. An overfeed section for stoker furnaces comprising a framework, apair of spaced headers mounted in said framework, a series of fluidconducting tubes extending substantially horizontally from one of saidheaders and being bent downwardly and reversely substantially in theform of a U and terminating in the other of said headers, a fuelsupporting means mounted on a portion of said tubes, a resilient supportfor said framework, and means comprising a vibrating mechanismoperatively connected to said framework for imparting rapid vibratoryimpulses thereto and consequently to said tubes and fuel supportingmeans whereby the fuel supported on said overfed section isprogressively advanced from one end thereof to the other.

CHARLES L. MYERS.

